Algebra Help

[The Man with ???'s]

I would very much like it if some people could remind me how to do these problems using the addition method. I kinda forgot how.

If you could help me with this one, that would be great.

6x-2y=10
x-2y=-5

I need to figure out what x and y are.

If ya can't help, thanks for looking.

 

[Gracie]

Using the addition method, first make sure that your variables are lined up. Here they already are. Then you need to see if a variable will cancel out by adding or subtracting the equations. Since you have -2y in both equations you need to subtract these equations to cancel out the y's . You subtract vertically


Ex. 6x - x = 5x and -2y - (-2y) = 0 and 10 - (-5) = 15


6x-2y=10
x-2y=-5
__________

5x + 0 = 15

Then solve for X 5x = 15 divide by 5 on both sides and x = 3

Then plug it in to find out the y valude for your solution. 3 -2y = -5

so y = 4

then test your answer (3.4) for both equations.

6(3)-2(4)=10 OK
(3)-2(4)=-5 OK

too cool!

 

[The Man with ???'s]

Hey, Thanks!
That works!
Nice job!
Now I can do my other problems! ^_^

But what happens when there is...
-3x+y=-2
-2=7x-y ?

 

[stapel]

1) Please post new questions as new threads, not as replies to old threads, where they tend to be overlooked.

2) Use the exact same method already illustrated: Line up the variables, and add down.

. . . . .-3x + y = -2
. . . . . .7x - y = -2
. . . . .---------------

Eliz.